Evaluation of asymptomatic central neuropathy in type I diabetes mellitus.

OBJECTIVES: Diabetic neuropathy is recognized as the most common clinical picture of nervous system disorders caused by diabetes mellitus (DM). Although peripheral and autonomic nervous system involvements are frequently encountered, there exists a few data about the incidence of central diabetic neuropathies. Central nervous system degeneration is a well known pathology in diabetic patients in the long term. It is possible to reveal central nervous system involvement at the early stages by using evoked potentials (EP). The aim of this study is to evaluate the auditory, visual and sensorial abnormalities in type I diabetic patients, who also have normal nerve conduction studies, with somatosensory, brainstem auditory and visual EP studies (SEP, VEP BAEP); to determine the frequency of these abnormalities and to investigate the relationship between other variables such as age, gender, duration of the diabetes and degree of the metabolic control. PATIENTS AND METHODS: A total of 36 asymptomatic type I DM children, ages ranging between 6-17 (mean age 11 +/- 3.24) taking insulin treatments were included in this study. Control group was made up of healthy children. EPs were evaluated and comparisons were made between the two groups. RESULTS: In a large group of diabetic children (47.2%), independent from parameters such as age, gender, glycemic control degree, auditory and visual deficits, retinopathy, joint movement limitation; but dependent on the peripheral SEP pathologies and disease duration there were central electrophysiological disturbances. In 13 (36.1%) of the patients SEP pathologies; in 9 (25%) of the patients VEP pathologies and in 14 (38.9%) of the patients BAEP pathologies were detected. CONCLUSION: Besides independent from peripheral pathologies, central nervous system involvement could also be observed in diabetic children. EP changes can be detected in asymptomatic patients that would be a predictor of future symptoms.

Tubular markers in children with insulin-dependent diabetes mellitus.

The aim of the present study was to investigate the prevalence of tubular dysfunction and to assess the clinical significance of low-molecular-weight proteinuria and enzymuria in children with insulin-dependent diabetes mellitus (IDDM). N.acetyl-beta-D-glucosaminidase (NAG) and beta-microglobulin (beta 2 M) excretion was determined in 52 children with insulin-dependent diabetes mellitus and 28 controls. Patients were grouped according to the duration of diabetes: group 1 (n = 7): less than one year; group 2 (n = 27): one to five years; groups 3 (n = 18): greater than five years. Both parameters were significantly increased in groups 2 and 3 compared to controls. Urinary beta 2 M levels correlated significantly with albuminuria and HbA1C, while urinary NAG levels correlated only with HbA1C. Two to four samples were obtained from 35 of 52 diabetic patients in the study group at one-month intervals. Of these, 23 patients had elevated NAG levels, and 22 patients increased beta 2 M excretion. However, only six patients displayed persistent enzymuria, and nine low-molecular-weight proteinuria. The mean (SD) of coefficients of variation of each patient was 50.45 (+/-28.24) for NAG and 68.25 (+/-42.57) for beta 2 M excretion. We concluded that early tubular dysfunction and/or damage occurs in IDDM but is not established in the majority of children.

Reduced immune response to hepatitis B vaccine in children with insulin dependent diabetes.

Twenty-four patients with moderately controlled insulin dependent diabetes with a duration of diabetes ranging from 2 to 10 years as well as 17 control subjects were vaccinated against hepatitis B virus using Gen Hevac B vaccine. The vaccine was injected 0.5 mL intramuscularly into the deltoid region on three separate occasions at intervals of 1 month. If subjects were still negative for anti-hepatitis B surface antigen (HBs) or had inadequate antibody after the third injection, a fourth administration of vaccine was given 3 months later. The mean anti-HBs titer was 243.3 +/- 97.2 mi.u./mL in control subjects and 39.8 +/- 53.2 in diabetic patients (P < 0.001). In the control group optimal protection was obtained in 100% of subjects, whereas 11 diabetic patients (45.8%) had low anti-HBs titer (< 10 mi.u./mL). All of 11 diabetic patients showed adequate (> 10 mi.u./mL) anti-HBs titer after the fourth dose of vaccine. In diabetic patients the most striking feature was the reduced CD4/CD8 ratio which was significantly lower (P < 0.001) than that of the control group. We conclude that diabetic children have an impaired immune response to hepatitis B vaccine. It is suggested that diabetic children should be vaccinated against hepatitis B virus with four injections instead of three.